DE102011080368B4 - Irradiation planning and irradiation with a quasi-cyclically moving target volume - Google Patents

Abstract

Method for irradiation planning for a quasi-cyclically moving target volume (18), comprising the following steps: - determining a first movement phase (G1) within a movement period of the target volume (18), - performing a first irradiation planning using a first position of the target volume (18) ) during the first movement phase (G1), - determining a second movement phase (G2) within the movement period of the target volume (18) and - carrying out a second irradiation planning using a second position of the target volume (18) during the second movement phase (G2), - wherein a total dose to be administered is divided into a first partial dose assigned to the first movement phase (G1) and a second partial dose assigned to the second movement phase (G2) and - with the first radiation planning and the second Irradiation planning in each case several segments (xi, yi) are determined over which the first partial dose and the second partial dose are to be applied in such a way that the application of the first partial dose takes place in segments (xi) during the first movement phase (G1), the application of a segment during a gating window of the first movement phase (G1) (xi) is ended and the application of a next segment dose assigned to a subsequent segment (xi + 1) is started.

Description

The invention relates to a method and a device for irradiation planning or for irradiation in a quasi-cyclically moving target volume.

Radiation therapy is an established procedure for the treatment of tumor diseases. Here, a high-energy treatment beam, for example, high-energy X-ray radiation, on a tissue to be irradiated such. B. directed a tumor.

Radiation therapy of moving target volumes, such. A lung tumor presents a challenge as the anatomy to be irradiated moves. It is important to apply the therapeutic radiation as specifically as possible in the tumor and to protect the surrounding tissue as well as possible. The movement can reduce the accuracy of the irradiation. One way to counteract this uncertainty is to use a larger safety margin, which, however, may lead to a higher dose burden on healthy tissue.

One method used in the irradiation of moving tumors is the so-called gating procedure. In the gating method, the movement cycle of the target volume is monitored and irradiation only takes place when the target volume is within a certain phase of the movement cycle suitable for the irradiation.

From G. Zhang et al., "Motion-weighted target volume and dose-volume histrogram: A practical apporoximation of four-dimensional planning and evalution, Radiotherapy and Oncology", 99, 2011, pp 67-72 a method is further known in which, in the context of an irradiation planning, so-called 4D computed tomography data are used in order to take into account movements to be expected during treatment in the planning.

Further, in E.Chin, K. Otto, "Investigation of a novel algorithm for true 4D-VMAT planning with comparison to tracked, gated and static delivery", Med. Phys., 38, 2011, pp. 2698-2707 A radiation treatment planning method is described in which a respiratory cycle is subdivided into six time periods and a tumor position is defined for each of these time segments, which is then used as the basis for the radiation planning for this period of time.

It is the object of the invention to provide a device and a method for irradiation planning or irradiation for a quasi-cyclically moving target volume, which allows rapid irradiation and at the same time tailor-made irradiation of the target volume while at the same time good protection of the surrounding tissue.

The object of the invention is achieved by the subject matters of the independent claims. Advantageous developments of the invention can be found in the features of the dependent claims.

• – Bestimmen einer ersten Bewegungsphase innerhalb einer Bewegungsperiode des Zielvolumens,
• – Durchführen einer ersten Bestrahlungsplanung unter Verwendung einer ersten Position des Zielvolumens während der ersten Bewegungsphase,
• – Bestimmen einer zweiten Bewegungsphase innerhalb der Bewegungsperiode des Zielvolumens,
• – Durchführen einer zweiten Bestrahlungsplanung für die zweite Bewegungsphase unter Verwendung einer zweiten Position des Zielvolumens während der zweiten Bewegungsphase,

wobei ein Aufteilen einer zu applizierenden Gesamtdosis auf eine erste Teildosis, die der ersten Bewegungsphase zugeordnet ist, und auf eine zweite Teildosis, die der zweiten Bewegungsphase zugeordnet ist, erfolgt.The method according to the invention for irradiation planning for a quasi-cyclically moving target volume comprises the following steps:

• Determining a first movement phase within a movement period of the target volume,
• Performing a first treatment planning using a first position of the target volume during the first movement phase,
• Determining a second movement phase within the movement period of the target volume,
• Performing a second treatment planning for the second movement phase using a second position of the target volume during the second movement phase,

wherein dividing a total dose to be applied to a first partial dose, which is associated with the first movement phase, and to a second partial dose, which is associated with the second movement phase occurs.

In the first treatment planning several segments are determined, with the aid of which the first partial dose is to be applied. The segments may indicate how the beam must be bounded laterally in order to achieve the desired dose distribution for the first partial treatment plan in the target volume, d. H. in order to meet targets with regard to the dose to be administered in the target volume and with regard to the maximum dose to be tolerated in the tissue to be preserved. The segments of the first treatment planning are adapted or optimized for the anatomical conditions in the object to be irradiated during the first movement phase.

Similarly, in the second treatment planning several segments are determined, with the help of which the second partial dose is to be applied. The segments may indicate how the beam has to be bounded laterally in order to achieve the desired dose distribution for the second partial treatment plan in the target volume. The segments of the second treatment planning are adapted or optimized for the anatomical conditions in the object to be irradiated during the second movement phase.

At the end of the treatment planning, an irradiation plan can be drawn up consisting of two (or more) partial treatment plans. The first partial irradiation plan comprises the parameters optimized for the irradiation of the target volume with the first partial dose in the first movement phase, the second irradiation plan comprises the parameters optimized for the irradiation of the target volume with the second partial dose in the second movement phase.

The invention is based on the knowledge that irradiation planning should already be appropriately designed for irradiation of a quasi-cyclically moving target volume.

A quasi-cyclically moving target volume is, for example, the lung or the liver, which move quasi-cyclically through the inhalation and exhalation movement, the beating heart, or to a certain extent even the intestine and the organs surrounding the intestine, if the intestinal peristalsis has some regularity.

It has been recognized that conventional gating methods, where the beam is applied during only a single gating time window within the motion period, have an adverse effect on the total exposure time since the portion of the motion period that is outside of the gating time window is for the actual irradiation remains unused.

The invention recognizes that two or more different gating time windows within one movement period may be used to irradiate the target volume. For example, a lung or liver tumor may be irradiated both during the inspiratory phase and during the exhalation phase.

Such irradiation is already planned during the treatment planning. This is achieved by determining two or more different movement phases or gating time windows within a movement period during the irradiation planning, during which a beam application is basically possible. Different anatomical conditions are then present in these different phases of movement. These different anatomical conditions, ie the different positions of the target volume, are included in the treatment planning.

A first partial irradiation plan for the irradiation of the target volume in the first movement phase is created, based on the anatomical conditions that exist in the first movement phase.

These anatomical relationships, for example, based on a four-dimensional data set such. B. a 4D CT can be determined. Subsequently, a second partial treatment plan for the irradiation of the target volume in the second movement phase is created, based on the changed compared to the first phase of movement anatomical conditions. As a function of the present movement, it is possible, in addition to the two irradiation phases, if desired, to plan further irradiation phases for which the same procedure applies. The total dose to be administered is thereby divided among the two (or more) different movement periods, such that the sum of the individual assigned sub-doses gives the total dose to be administered. The radiation planning for the individual movement phases can then be carried out using the pre-divided total dose on the two (or more) sub-doses.

The first movement phase can, for. B. have a larger proportion of the total duration of a movement cycle than the second phase of movement. The division can then take place such that the first partial dose is greater than the second partial dose. In particular, the distribution of the total dose can be proportional to the proportion of the duration of the respective movement phases in the total duration of the movement cycle.

For example, two phases of movement associated with the expiratory position and the inspiratory position may be used. For example, the duration of the expiratory position may be on average 40% of the exercise cycle and the duration of the inspiratory position 20% of the exercise cycle.

Accordingly, 2/3 of the total dose to be administered is assigned to the expiratory phase and 1/3 of the total dose of the inspiration phase.

An irradiation plan or the two partial irradiation plans can be implemented by a radiation therapy device or its control unit, so that the radiation therapy device is controlled according to the irradiation planning for the dose application.

The inventive device for irradiation planning for a quasi-cyclically moving target volume has a computer unit which is configured:
for determining a first movement phase within a movement period of the target volume,
for performing a first treatment planning using a first position of the target volume during the first movement phase,
for determining a second movement phase within the movement period of the target volume,
for performing a second irradiation planning for the second movement phase using a second position of the target volume during the second movement phase,
wherein dividing a total dose to be applied to a first partial dose, which is associated with the first movement phase, and to a second partial dose, which is associated with the second movement phase occurs.

The device can be designed to carry out a method for irradiation planning, for example by appropriate configuration or programming of the computer unit.

• a) Überwachen der Bewegung des Zielvolumens,
• b) Feststellen, dass das Zielvolumen in eine erste Bewegungsphase eingetreten ist, wobei die erste Bewegungsphase ein erster Abschnitt eines Bewegungszyklus des Zielvolumens ist,
• c) Applizieren eines Teils einer ersten Teildosis der Gesamtdosis, die der ersten Bewegungsphase zugeordnet ist, während sich das Zielvolumen in der ersten Bewegungsphase befindet,
• d) Feststellen, dass das Zielvolumen in eine zweite Bewegungsphase eingetreten ist, wobei die zweite Bewegungsphase ein zweiter Abschnitt des Bewegungszyklus des Zielvolumens ist,
• e) Applizieren eines Teils einer zweiten Teildosis der Gesamtdosis, die der zweiten Bewegungsphase zugeordnet ist, während sich das Zielvolumen in der zweiten Bewegungsphase befindet,

wobei die Schritte b) bis e) mehrfach wiederholt werden, bis die gesamte erste vorbestimmte Teildosis der Gesamtdosis appliziert worden ist, während sich das Zielvolumen in der ersten Bewegungsphase befunden hat, oder bis die gesamte zweite vorbestimmte Teildosis der Gesamtdosis appliziert worden ist, während sich das Zielvolumen in der zweiten Bewegungsphase befunden hat. The method according to the invention for irradiation for a quasi-cyclically moving target volume comprises the following steps:

• a) monitoring the movement of the target volume,
• b) determining that the target volume has entered a first movement phase, the first movement phase being a first portion of a movement cycle of the target volume,
• c) applying a portion of a first partial dose of the total dose associated with the first movement phase while the target volume is in the first movement phase,
• d) determining that the target volume has entered a second motion phase, the second motion phase being a second portion of the motion cycle of the target volume,
• e) applying a portion of a second partial dose of the total dose associated with the second movement phase while the target volume is in the second movement phase,

wherein steps b) to e) are repeated a plurality of times until the entire first predetermined partial dose of the total dose has been administered while the target volume was in the first movement phase or until the entire second predetermined partial dose of the total dose has been applied has found the target volume in the second movement phase.

This can ultimately lead to step b) to e) being repeated several times until the entire first predetermined partial dose of the total dose has been administered while the target volume was in the first movement phase and until the entire second predetermined partial dose is applied to the total dose while the target volume has been in the second movement phase, wherein steps b) to e) for a movement phase can be skipped if the entire planned partial dose for this movement phase has already been applied.

In this irradiation method, therefore, the irradiation takes place in one movement cycle at 2 (or more) different times or sections.

When the target volume enters the first movement phase of the movement period, a first gating time window opens. During this gating time window, the beam application takes place, specifically a part of the first partial dose that was previously determined during the irradiation planning and assigned to the first movement phase and for which the first partial irradiation plan has been created is applied. This beam application takes place in accordance with the parameter settings determined for the first partial irradiation plan. As soon as the target volume exits the first movement phase of the movement period, the first gating time window ends and the beam application is interrupted.

Subsequently, when the target volume enters the second movement phase of the movement period in the same movement cycle, the second gating time window opens. During this gating time window again a beam application takes place. A part of the second partial dose, which is assigned to the second partial treatment plan and which was previously determined during the radiation planning for the second movement phase, is applied. This application takes place in accordance with the settings determined for the second partial treatment plan. As soon as the target volume emerges from the second movement phase, the beam application is interrupted again.

If appropriate, the target volume can be irradiated in an analogous manner during further predefined gating time windows in the same movement cycle.

In the subsequent cycle of movement, in turn, is waited until the target volume enters the first movement phase. In the current gating time window, which is assigned to the first movement phase, another beam application takes place, with which in turn a part of the first partial dose, which is assigned to the first partial treatment plan, is applied. If the target volume again enters the second movement phase in the same movement cycle, a gating time window, which is assigned to the second movement phase, opens again. Once again, part of the second partial dose, which is assigned to the second partial treatment plan, is emitted.

This procedure can be continued. In successive cycles of movement, the target volume is therefore irradiated twice (or more times) per cycle of movement with alternating parameter settings, each specific have been previously determined for different movement phases and deposited in partial treatment plans.

There is thus an alternating repetition of steps b) to e) in successive cycles of motion. This can be carried out until the entire first partial dose or until the entire second partial dose has been applied as planned. Subsequently, the remainder of that partial dose is applied which has not yet been completely applied, wherein the irradiation takes place in the corresponding irradiation phase.

The part of the movement period available for irradiation, which is significantly restricted by the conventional gating method, is utilized in an improved way, since now several gating windows are available during one movement period.

In addition, smaller dose deviations can be better absorbed. For each gating window, a small error can occur. The fact that the dose is applied in several phases of movement and thus in different gating time windows, small deviations can be better averaged.

In particular, if in the treatment planning the distribution of the total dose to the individual sub-doses corresponding to the duration of the individual movement phases in relation to the total duration of the movement cycle has taken place, the total dose can be applied very quickly, since the period of time available during the movement cycles for the irradiation stands, can be exploited by this design particularly favorable. The remainder of that partial dose, which is still to be applied, when the other partial dose has already been completely radiated, is then particularly low.

With such an irradiation method, the movement cycle is better utilized compared to irradiation methods in which only one gating time window is used for the irradiation during one movement cycle. Nevertheless, since a gating method is used, the irradiation can be excluded during certain phases of movement, during which z. B. the target volume moves too fast than that a tailor-made irradiation of the target volume could be performed.

The first and the second movement phase may be such that the target volume is located between a gating window of the first movement phase and the subsequent gating window of the second movement phase in a third movement phase. During the third movement phase, no beam application takes place, but a change in the machine parameters from a first setting determined for the application of the first partial dose to a second setting determined for the subsequent application of the second partial dose.

With this embodiment, that movement phase in which no beam application takes place, advantageously exploited to change the machine parameters of the radiotherapy device from the application of the first partial dose on the application of the second partial dose, z. B. with regard to the segment forms to be applied.

The application of the first and / or second partial dose during the first and second movement phase takes place in segments. For example, a segment may be characterized by a particular collimator aperture that temporally limits the treatment beam.

The method can now be designed such that only one segment is applied during a gating window of the first movement phase. This is easy to integrate in a radiotherapy device or in its control, as compared to a rapid switching from one segment to the next during the same gating time window makes high demands on the speed of changing the parameter settings.

However, during a gating window of the first movement phase, the application of a segment dose assigned to a segment is ended and the application of a next segment dose assigned to a subsequent segment is started in the same gating time window, however, is also provided for the method. This allows an even faster application of the total irradiation dose, but requires a more complex control of the radiotherapy device or a higher demand on the speed of a change of the parameter settings. Within a gating window, however, several different segments can be applied in this way.

In a further embodiment of the method, the application of a segment dose assigned to a segment can be started during a gating window and continued during the subsequent gating window of the same movement phase. In this way, the possibility is allowed to apply also incomplete segment doses in a gating time window. In the case of an incomplete application, the irradiation is continued in the next gating time window with the parameter setting assigned to this segment until the planned accumulated dose has been reached.

• – eine Strahlenquelle zum Bereitstellen von therapeutischer Strahlung, mit der ein Zielvolumen bestrahlbar ist,
• – eine Bewegungsüberwachungseinrichtung, die ausgebildet ist, die Bewegung eines Zielvolumens zu ermitteln,
• – eine Steuerungsvorrichtung, welche konfiguriert ist, die Strahlapplikation unter Verwendung der von der Bewegungsüberwachungseinrichtung ermittelten Bewegung des Zielvolumens zu steuern, wobei die Steuerungsvorrichtung konfiguriert ist, im Betrieb ein Bestrahlungsverfahren nach einem der Ansprüche 6 bis 9 auszuführen.

The irradiation device according to the invention comprises:

• A radiation source for providing therapeutic radiation, with which a target volume can be irradiated,
• A motion monitoring device, which is designed to determine the movement of a target volume,
• A controller configured to control the beam application using movement of the target volume determined by the motion monitor, the controller being configured to perform an irradiation method according to any one of claims 6 to 9 in use.

The control device may thus determine whether to perform a machine adjustment associated with the first movement phase, if there is a gating window associated with the first movement phase, or if to perform a machine adjustment associated with the second movement phase if a corresponding gating window is present.

The preceding and following description of the individual features, their advantages and their effects relates both to the device category and to the process category, although this is not explicitly mentioned in detail in each case; The individual features disclosed in this case can also be essential to the invention in combinations other than those shown. Likewise, the description of advantages and effects that have been described in connection with the treatment planning applies mutatis mutandis to the irradiation and vice versa.

Embodiments of the invention having embodiments according to the features of the independent claims and dependent claims can be found in the following drawing, but are not limited thereto. Show it:

1 a schematic overview of a radiotherapy device and an irradiation planning device,

2 a diagram showing the time course of the movement over several cycles of motion, and with reference to which the method according to the invention for irradiation planning with a plurality of gating time windows is explained in a movement cycle,

3 a flowchart for an embodiment of the treatment planning, and

4 a flowchart of an embodiment of the irradiation.

1 shows in a crude schematic way the construction of a radiotherapy device 11 and an irradiation planning device 13 ,

The radiotherapy device 11 has a therapeutic radiation source 15 with which a treatment beam 17 on a patient 19 can be directed. With the treatment beam 17 can be, for example, the quasi-cyclically moving lung 18 be irradiated. Furthermore, the radiotherapy device has 11 about devices with which the treatment beam 17 can be modified so that it can be radiated according to an irradiation plan. These devices include, for example, a collimator 21 with which so-called segments of an irradiation planning data record can be set and emitted.

A segment is by a certain dose and by a certain collimator, which is the treatment beam 17 limited laterally in its extent and with which the dose is emitted, characterized.

The radiotherapy device 11 can - as shown here - via a rotatable gantry 23 dispose, with the individual segments from different directions on the patient 19 can be directed.

A control device 25 for the radiotherapy device 11 controls the components of the radiotherapy device 11 such that an irradiation plan 27 that has an interface of the control device 25 is provided with the radiotherapy device 11 can be applied.

The control device 25 also has an interface through which data can be fed, which is the movement of the target volume in patients 19 characterize. Such movement data can, for example, via external sensors 29 to be recorded.

The irradiation planning device 13 is usually in a programmed for irradiation planning and configured computer unit 33 realized.

The computer unit 33 has an input for loading a patient record 35 , for example, a four-dimensional computed tomography (4D-CT) data set.

Based on this, a user can create a radiation planning by entering specific specifications according to which the irradiation has to take place. Subsequently, the treatment plan 27 determined. These are ultimately those Determined parameter settings with which the specifications regarding a desired irradiation can be optimally fulfilled, and in a record, the treatment plan 27 , deposited.

The control device of the radiotherapy device 25 and radiation planning device 31 may be designed in such a way that they can be used to carry out the methods described in this application.

The treatment plan 27 then includes two (or more) partial treatment plans 37 . 39 ,

The principle of the invention is based on 2 explained in more detail.

The upper curve 51 in 2 shows the temporal representation of the respiratory movement M of the lung based on a one-dimensional signal. Such a signal can, for example, from an external sensor, such. B. a breathing sensor.

The upper curve 51 shows several consecutive motion cycles. Also shown are those phases of movement in the movement cycles which correspond to the inhalation position G ₂ or the exhalation position G ₁ . In the inhalation position G ₂ and in the exhalation position G ₁ are those motion phases in which a beam application is basically possible. In motion phases that lie between the inhalation position and the exhalation position, a beam application is not possible.

This situation is in the second curve below the respiratory curve 53 which shows the gating time windows, that is to say those temporal sections in which the treatment beam for dose application can in principle be switched on.

Consequently, there are two gating time windows in each movement cycle, a gating time window of the inhalation G ₂ and a gating time window of the exhalation G ₁ .

In the third turn 55 those time periods are shown in which actually take place an irradiation (Engl.: "Beam ON" for beam-on ").

The time segments are also labeled x _i and y _i , respectively. X _i denotes those segments which are associated with a first partial treatment plan (exhalation phase), y _i those segments which are associated with a second partial treatment plan (inhalation phase).

One embodiment of the irradiation is shown by the irradiation during the exhalation phase (G ₁ ).

During this irradiation, the first partial irradiation plan is radiated, ie the segments x _i . The dose associated with the segment x ₁ is applied during the first gating time window of the exhalation phase. However, at the end of this first gating time window, the dose of segment x ₁ is not yet fully applied. Therefore, the irradiation of the segment x _{1 is continued} in the subsequent gating time window of the exhalation phase. During this gating time window, the irradiation of the x ₁ segment dose is completed before the end of the gating time window has been reached.

The remaining time of the gating time window is used to set the radiation therapy device for the irradiation of the next segment x ₂ and to apply the dose associated with this segment. Again, the gating window times out before the entire dose of segment x _{2 has been} applied. Therefore, the irradiation continues in the next gating window of the exhalation phase.

A further embodiment of the irradiation is shown by the irradiation during the inhalation phase (G ₂ ). In this movement phase, the second partial irradiation plan, ie the segments y _i , is radiated.

The irradiation is carried out such that only one segment y _i or its associated dose can be emitted during a gating time window. Once the radiation of this dose is completed, the remaining time in this gating window will not be used for further radiation. The dose of the next segment will be started in the next gating window and - if possible - finally irradiated.

In this embodiment, therefore, a segment during a gating window or during multiple gating windows - if more are needed - applied. However, during a gating window, no different segments are selected and applied.

The intervals indicated by m indicate the phases in which no beam application is possible, and in which the machine parameters are changed from the irradiation of the first partial irradiation plan to the irradiation of the second partial irradiation plan and vice versa.

3 shows a schematic flow diagram, on the basis of which an embodiment of the irradiation planning method will be explained.

In a first step, a first movement phase is determined within a movement period of the target volume for which a first partial treatment plan is to be created (step 61 ).

Subsequently, a second movement phase is determined within the movement period of the target volume, which is different and disjoint from the first movement phase, and for which a second partial treatment plan is to be created (step 63 ).

The two (or more) motion phases may be determined and selected using a four-dimensional CT dataset.

Subsequently, the duration of the first movement phase and the duration of the second movement phase are compared with each other. The total dose to be administered is calculated according to the ratio of the duration of the first movement phase and the duration of the second movement phase to a first partial dose, which is to be applied only during the first movement phase, and to a second partial dose, which is only during the second movement phase to be applied, split (step 65 ). The weighting of the fractions is therefore based on the length of the estimated residence time of the target volume in the respective phases of movement.

Subsequently, a first partial treatment plan is determined, based on the anatomical conditions during the first movement phase, and with which the first partial dose of the total dose is to be applied. For the determination of the first partial irradiation plan known methods for irradiation planning can be used (step 67 ).

Subsequently, a second partial treatment plan for the second movement phase is determined, based on the anatomical conditions of the second movement phase and with which the second partial dose of the total dose is to be applied. For the determination of the second partial treatment plan, known methods for irradiation planning can be used (step 69 ).

The treatment plan comprising the first partial treatment plan and the second partial treatment plan is stored (step 71 ).

4 shows a schematic flow diagram, such as an irradiation plan, which according to a method according to 3 has been created, can be radiated.

During the irradiation of the target volume, the movement of the target volume is continuously monitored. For example, a motion signal is recorded and analyzed (step 81 ).

From this motion signal, a gating signal is now determined, d. H. a signal that signals the radiotherapy device when a gating window begins ("gate-on") and when a gating window ends ("gate-off"). This can be z. B. by a separate system, which is interposed between the motion monitor and the radiotherapy system, performed, or by a control device of the radiation therapy system.

The device with which the gating signal is determined from the movement signal can additionally provide information indicating which movement phase the gating signal is associated with. This can be done in different ways. The gating signal for the different phases of movement can z. B. be made available to the irradiation system via one or more lines. The gating signal, if transmitted over a line, can be encoded to associate the gating signal with the motion phase. The coding could z. B. in a TCP / IP protocol, a complete signal with assignment to the motion phases, in an analog signal, the coding could be realized by different voltage levels or different frequency coding, etc ..

However, it is also conceivable to transmit the gating signal uncoded to the irradiation system, the irradiation system then determining the assignment to the movement phases.

It is determined that the target volume enters the first movement phase (step 83 ). While the target volume is in this first movement phase, the application of the first partial irradiation plan begins (step 85 ). As soon as the target volume emerges from the first movement phase, the irradiation of the first partial irradiation plan stops.

It is then determined that the target volume enters the second movement phase (step 87 ). In the meantime, the radiotherapy device for the radiation of the second partial treatment plan is readjusted. While the target volume is in this second movement phase, the application of the second partial treatment plan begins (step 89 ). As soon as the target volume emerges from the second movement phase, the irradiation of the second partial irradiation plan stops.

step 83 until step 89 are repeated until the first partial treatment plan or the second partial treatment plan has been completely applied.

Subsequently, the irradiation of the remaining, not completely applied partial treatment plan takes place (step 91 ).

After complete irradiation of the first and second treatment plan, the irradiation session is completed (step 93 ).

LIST OF REFERENCE NUMBERS

11

radiation therapy device

13

Irradiation planning device

15

therapeutic radiation source

17

therapeutic treatment beam

18

lung

19

patient

21

collimator

23

gantry

25

control device

27

treatment plan

29

external sensor

33

computer unit

35

Planning record

37

first partial treatment plan

39

second partial treatment plan

51

first curve (motion signal, example lung)

53

second curve (gating signal)

55

third curve (beam on signal)

G ₁

exhalation

G ₂

inhalation phase

x _i , y _i

Segments of the individual radiation phases

m

Intervals without radiation

61-71

steps 61 - 71

81-93

steps 81 - 93

Claims (10)

Method for irradiation planning for a quasi-cyclically moving target volume ( 18 ), comprising the following steps: determining a first movement phase (G ₁ ) within a movement period of the target volume ( 18 ), - performing a first treatment planning using a first position of the target volume ( 18 ) during the first movement phase (G ₁ ), - determining a second movement phase (G ₂ ) within the movement period of the target volume ( 18 ) and - performing a second treatment planning using a second position of the target volume ( 18 ) during the second movement phase (G ₂ ), - wherein a division of a total dose to be applied to a first partial dose, which is associated with the first movement phase (G ₁ ), and a second partial dose, the second movement phase (G ₂ ) is assigned , takes place and - wherein in each case a plurality of segments (x _i , y _i ) are determined during the first irradiation planning and in the second irradiation planning, via which the first partial dose and the second partial dose are to be applied, such that the application of the first partial dose during the the first movement phase (G ₁ ) takes place in segments (x _i ), wherein the application of a segment dose associated with a segment (x _i ) is ended during a gating window of the first movement phase (G ₁ ) and the application of a subsequent segment (x _{i + 1} ) associated with the next segment dose. The method of claim 1, wherein the first movement phase (G ₁ ) has a greater proportion of the total duration of a movement cycle than the second movement phase (G ₂ ), and wherein the splitting is such that the first partial dose is greater than the second partial dose. The method of claim 2, wherein the distribution of the total dose is proportional to the proportion of the duration of the movement phases in the movement cycle. Apparatus for irradiation planning ( 13 ) for a quasi-cyclically moving target volume ( 18 ), with a computer unit ( 33 ) which is configured: - for determining a first movement phase (G ₁ ) within a movement period of the target volume ( 18 ), For performing a first treatment planning using a first position of the target volume ( 18 during the first movement phase (G ₁ ), for determining a second movement phase (G ₂ ) within the movement period of the target volume ( 18 ) For carrying out a second irradiation planning for the second movement phase using a second position of the target volume ( 18 ) during the second movement phase (G ₂ ), - wherein a division of a total dose to be applied to a first partial dose, which is associated with the first movement phase (G ₁ ), and a second partial dose, the second movement phase (G ₂ ) is assigned , takes place and - wherein in each case a plurality of segments (x _i , y _i ) are determined during the first irradiation planning and in the second irradiation planning, via which the first partial dose and the second partial dose are to be applied, such that the application of the first partial dose during the first movement phase (G ₁ ) takes place in segments (x _i ), wherein during a gating window of the first movement phase (G ₁ ) the application is assigned to a segment (x _i ) Segment dose is terminated and the application of a next segment dose associated with a subsequent segment (x _{i + 1} ) is started. Apparatus according to claim 4, wherein the apparatus is adapted to carry out a method according to one of claims 1 to 3. Method for irradiating a quasi-cyclically moving target volume ( 18 ), comprising the following steps: a) monitoring the movement of the target volume ( 18 ), b) determining that the target volume ( 18 ) has entered a first movement phase (G ₁ ), the first movement phase (G ₁ ) being a first section of a movement cycle of the target volume (G ₁ ). 18 ), c) applying a portion of a first partial dose of the total dose associated with the first movement phase (G ₁ ) while the target volume ( 18 ) In the first movement phase (G _1), d) determining that the target volume (in a second movement phase G ₂₎ has occurred, wherein the second movement phase (G ₂₎ (a second portion of the cycle of movement of the target volume 18 ), e) applying a portion of a second partial dose of the total dose associated with the second movement phase (G ₂ ) while the target volume ( 18 ) is in the second movement phase (G ₂ ), - wherein steps b) to e) are repeated until the entire first partial dose of the total dose has been applied, while the target volume ( 18 ) in the first movement phase (G ₁ ), or until the entire second partial dose of the total dose has been administered while the target volume ( 18 ) in the second movement phase (G ₂ ), - wherein the application of the first partial dose during the first movement phase (G ₁ ) in segments (x _i ) takes place and - wherein during a gating window of the first movement phase (G ₁ ) the Application of a segment (x _i ) associated segment dose is terminated and the application of a subsequent segment (x _{i + 1} ) associated next segment dose is started. The method of claim 6, wherein the target volume ( 18 ) between a gating window of the first movement phase (G ₁ ) and the subsequent gating window of the second movement phase (G ₂ ) in a third movement phase (m), and wherein during the third movement phase (m) no beam application takes place and machine parameters of a first, for the application of the first partial dose determined parameter setting to a second, for the subsequent application of the second partial dose determined parameter setting to be changed. The method of claim 6 or 7, wherein the application of the first partial dose during the first movement phase (G ₁₎ in segments (x _i) is carried out, and wherein (G ₁₎ only a segment (x _i) during a gating window of the first phase of movement is applied. Method according to one of claims 6 to 8, wherein the application of the first predetermined partial dose during the first movement phase (G ₁ ) in segments (x _i ), and wherein during a gating window, the application of a segment (x _i ) associated segment Dose is started and continued during the subsequent gating window of the same movement phase. Irradiation device ( 11 ), comprising: - a radiation source ( 15 ) for providing therapeutic radiation ( 17 ), with which a target volume ( 18 ) is irradiated, - a movement monitoring device ( 29 ), which is designed to determine the movement of a target volume ( 18 ), - a control device ( 25 ), which is configured to use the beam application using the motion monitoring device ( 29 ) determined movement of the target volume ( 18 ), the control device ( 25 ) is configured to perform an irradiation method according to any one of claims 6 to 9 in operation.

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